Pneumonia Flashcards
How can you diagnose pneumonia?
Signs of lower respiratory tract infections (fever/cough/phlegm/crepitations or bronchial breathing) + CXR changes
What is CAP?
Community acquired pneumonia
- Infection that has been acquired without any contact with healthcare services
What is HAP?
Hospital acquired pneumonia
- New onset of symptoms along with a compatible x-ray developing >48 hours after the patient’s admission to hospital
What are the sub-categories of HAP?
Early onset
- Within 4-5 days of admission
- More likely to be antibiotic-sensitive bacteria
Late onset
- > 5 days of admission
- More likely to be antibiotic resistant bacteria
What is VAP?
Ventilator associated pneumonia
- Occurs in patients on mechanical ventilation
What are the typical causes of CAP?
o Streptococcus Pneumoniae (most common) o Haemophilus influenzae o Moraxella catarrhalis o Klebsiella pneumoniae o Staphylococcus aureus o Viruses
Mainly gram +ve cocci
What are the atypical causes of CAP?
Legions of psittaci MCQs -> atypical pneumonia • Legionella pneumophila • Chlamydophila Psittaci • Mycoplasma pneumoniae • Chlamydophila pneumoniae • Q-fever (Coxiella burnetiii)
What viruses commonly cause CAP?
- Influenza A and B
- Adenovirus
- Para-influenzae
- Respiratory synctal virus
- SARS-CoV-2
What is distinctive about legionella species?
- Caused by infected water supplies or air conditioning units (holiday)
- Causes SIADH which causes Hypotranaemia
What is distinctive about mycoplasma pneumoniae?
- Causes erythema multiforme
- Tends to effect younger patients
What is distinctive about chlamydia pneumoniae?
- Occurs in outbreaks in families and institutions
- Extremities of age vulnerable
What is distinctive about coxiella burnetii?
- Exposure to animals and bodily fluids
What is distinctive about chylamydia psittaci?
- Infected birds
- Can occasionally cause hepatosplenomegaly
How do you treat atypical CAP organisms?
Macrolides
- Need to be treated with antibiotics which act in intracellular space as they do not have a cell wall (penicillin and cephalosporins act on the cell wall)
What are the common causes of late-onset HAP?
o Staphylococcus Aureus (including MRSA)
o Enterobacteria: E. coli, Klebsiella sp., Enterobacter sp., Serratia
o Pseudomonas sp.
o Environmental gram negatives: Acinetobacter ap., Stenotrophomonas, maltophilia
What is distinctive about staphylococcus aureus?
- Grame +ve coccus
- Upper respiratory tract commensal
- Looks like bunch of grapes under microscope
What is distinctive about enterobacteria?
- Grame -ve bacilli
- GI tract commensals
- May be multi-drug resistant
What is distinctive about the pseudomonas species?
- Gram -ve bacillus
- Resistant to many antibiotics
What is distinctive about environmental gram negatives?
- Multi drug resistant and difficult to treat
What causes aspiration pneumonia?
Inhalation of stomach contents or secretions of the oropharynx leading to lower respiratory tract infection
Where is aspiration pneumonia most commonly seen and why?
Right lower lobe (RLL)
o Right main bronchus is straighter from the trachea compared to the left main bronchus.
What is the most common fungal cause of pneumonia?
Pneumocystis jirovecii
In which patients is fungal pneumonia most commonly seen?
- Patients with altered cell-mediated immunity (immunodeficiency -> HIV, immunosuppression -> after transplantation)
- Patients with a severe underlying respiratory condition (COPD, CF).
What is distinctive about streptococcus pneumoniae?
- Gram +ve coccus
- Can be detected in blood culture or urinary antigen
- Vaccine available
- Causes rust coloured sputum
What is distinctive about haemophilus influenzae?
- Gram -ve bacillus
What is distinctive about moraxella catarrhalis?
- Associated with immunocompromised patients and those with chronic lung disease
What is distinctive about klebsiella pneumoniae?
- Commensal organism of the GI tract
- Tends to affect upper lobes
What is distinctive about staphylococcus aureus?
- Gram +ve coccus
- IVDU at risk
- Chronic lung pathology a risk factor
